Construction of next generation local transmission

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With the rapid progress of optical communication technology, the cost of building a high starting point multi service transmission platform has been greatly reduced, and the development of services is making great changes in telecommunications. Obviously, when the vast majority of the information to be carried by the network is data services (especially the booming streaming media services), it is very difficult and uneconomical to expand the network to adapt to the traditional narrowband services to meet the challenges of the broadband world. Building a new platform is a strategic trend that does not take people's subjective consciousness as the transfer. Based on this opportunity, how to choose the best construction scheme to face the challenges brought by the reform of the telecommunications industry? The following will be analyzed from two aspects

the construction of biplane is the inevitable trend of network evolution

although the traditional SDH technology is increasingly difficult to meet the needs of business development, the huge infrastructure it has formed cannot be easily abandoned overnight, let alone the digital business is still the basis for the profitability of the telecommunications industry. So the concept of MSTP is introduced into transmission. At this stage, a new generation of MSTP equipment compatible with pure SDH and pure data processing should be used to realize bottleneck free IP access. Types I, II and III are dumbbell shaped samples. However, traditional operators have basically built a perfect SDH transmission according to the hierarchical model of backbone layer, tandem layer and access layer. Introducing MSTP equipment into such a network requires layer by layer analysis

in the access layer, the network coverage is wide, and the equipment is required to adapt to various complex environments; With a large number of nodes, the investment in equipment and optical cables is very huge, and the integrated 155/622m equipment with high cost performance ratio is more and more widely used; The traffic volume of single point access is small, the service burst characteristics are obvious, and there is no bandwidth bottleneck for the time being, which can be solved by dividing the ring or increasing the optical interface rate; The access of data services is not predictable, and it is not necessary to upgrade all nodes to MSTP devices in advance. Therefore, in consideration of investment protection, the access layer network that has been built can not be reconstructed in a large area, and a new generation of MSTP equipment can be used for supplementary coverage for data hotspot areas and key customer applications

at the backbone/core layer, the business volume fluctuates slightly after convergence. The network structure is generally a stable high-speed ring, and business security is emphasized

in the convergence layer, the number of nodes is small, mainly 2.5G rings. With the rapid growth of traffic, the problem of bandwidth limitation has become increasingly prominent, and many convergence rings are facing the problem of capacity expansion. On the other hand, the convergence layer has not only played the role of transparent transmission after service convergence, but also can not solve the bandwidth bottleneck only by capacity expansion. The accessed IP services and ATM services must be processed at this layer to achieve statistical multiplexing of bandwidth. Therefore, the convergence layer has the need to create new rings and process new services, which is the best level for introducing MSTP equipment. In the access layer, there is no problem for SDH to achieve full geographic coverage, but full service coverage cannot be achieved. MSTP equipment should be introduced in some nodes as a supplement

at present, an optimization scheme for some local transmission applications is to selectively add data boards in "hot spot" areas or replace the old 2.5G equipment with 2.5G MSTP equipment with greater cross capacity and data processing capacity, and mix them with the original equipment

the idea proposed in this paper is to use new MSTP equipment to independently build a convergence layer plane. The original SDH convergence layer remains as plane a, and a layer of MSTP convergence layer is superimposed on it as plane B. The new network mainly completes the transmission of new services, and can divert the original network services. The new access layer nodes and the loops separated from the original access layer due to bandwidth constraints can be connected to the new MSTP B plane

in terms of TDM service transmission, the original network can still achieve high efficiency. Therefore, considering the investment, the old platform will not be replaced at one time. However, since the upgrading of the network is the general trend, when building a new platform, it should maintain its relative independence from the original platform, instead of mixing old and new equipment. This is because:

the construction efficiency of the original mixing group is not high, which increases the workload of network cutting and safety hazards, and also causes waste of replaced equipment. The biplane construction mode is relatively simple. It can be easily built independently according to the optical cable route, without affecting the topology stability and service security of the original convergence layer a

the mixed and combined scheme is difficult to adopt different transmission strategies such as convergence and sharing for data services, and can not really provide strong support for data services, which is not in line with the trend of network development. In addition to adopting flexible transmission strategies for different users and services, a separate MSTP B plane can also efficiently transmit data services in the SDH VC channel

therefore, the a/b biplane network scheme is the best means to replace the old with the new in the transitional period, and it is an inevitable trend of development

building biplane is the need to optimize network topology.

according to the "barrel theory", if telecom operators want to form their own comprehensive competitive advantage, they must flatten their shortest plank, achieve balanced development and provide the best service. There is no doubt that the traditional SDH platform has shortcomings, even more than one. The new MSTP B plane can make up for the shortcomings of the original platform in the following aspects:

--b plane not only provides richer service interfaces, but also can choose different topologies. This difference will fill the gap of a plane in some regions or services, and enable the network to achieve full service and full geographical coverage

-- simplify the scheduling of cross ring services. In the original a plane, the service channel between the two nodes may span different convergence layer loops. After adding a B plane, due to topology optimization, some circuits between the convergence layer loops in the original a plane can be changed into ring circuits in the B plane, and its TG is 60 ~ 65 ℃ to provide end-to-end channels more flexibly

-- during the construction of plane a, the laying amount of optical cables is not enough, so there are many unreasonable places in the network route selection. Some ADM nodes may actually use the same optical cable to go in and out, and there are a lot of hidden dangers of single node failure in the network. The new plane can make full use of the new fiber path, and effectively solve the above problems by selecting the optimal topology and dual node access. The annual demand for plastic film is more than 600000 tons. At the same time, the load sharing of the biplane network also greatly enhances the business security

-- the access transmission of wireless base station service is optimized. For mobile operators, the B plane can divert some BTS access ring services of the a plane. In this way, when any convergence layer node fails, only some BTS will fail. The remaining working BTS can increase the coverage by increasing the power, which can greatly improve the security of the network

-- it provides a new idea for the effective use of wired access. In recent years, with the emergence and rapid development of cellular mobile communication systems and fixed wireless access systems, the role of wired access technology will change fundamentally, that is, it will mainly support broadband data applications. MSTP will assist the current wired access to adapt to this role transformation, and provide rich service interfaces and flexible bandwidth allocation mechanisms. For example, for fixed line operators, plane B can transmit ip/atm services such as DSLAM services and stream media services such as IPTV

-- the new plane facilitates fast access to new services. With the MSTP convergence layer B plane, it can quickly carry out various metropolitan data services and provide key customer solutions through various access methods. The new platform can also provide bearer functions for IP services and 3G services of NGN in the future

the construction of dual plane network will bring better cost-effective products and services to telecom operators. As a relatively independent new platform, MSTP B plane will have a large choice in equipment selection, and it is convenient to introduce new manufacturers locally. From the perspective of enterprise operation, introducing the equipment of the second manufacturer to build MSTP B plane can effectively reduce the cost of network expansion and obtain the best cost-effective products and services. By building the second plane, we can expand the scope of technology selection, keep pace with the world's advanced communication technologies, and select products with different characteristics and advantages according to the specific characteristics and problems of our own network, so as to find the most appropriate solutions. (end)

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